Screen for paper pulp



Dec. 9, 1924-.

. J. W. HAMMOND SCREEN FOR PAPER PULP Filed April 2. 1924 `2'Sheets'-Sheet l Dec. 9, 1924. f t 1,518,501

J. W. HAMMOND SCREEN PQR PAPER PULP Filed April 2, 1924 2 Sheets-Sheet 2 Patented Dec. 9, 1924.

UNITED STATES" PATENT OFFICE.

JAMES W. HAMMOND, OF WALPOLE, MASSACHUSETTS, ASSIGNOR TO BIRD MACHINE COMPANY, OF WALPOLE, MASSACHUSETTS, A CORPORATION OE MASSACHUSETTS.

- a SCREEN FOR PAPER PULP.

Application led April 2, 1924. 'Serialx No. 703,778.

To all whom z't may concern:

Be it known that I, JAMES W. HAMMOND, a citizen of the United States, residingY at WValpole, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Screens for Paper Pulp, of which the following 1s a specification.

This invention relates to screens of the in-4 flow type for paper stock or pulp Iin which the stock is fed to a vat wherein the screen is partially submerged, the finer material passing inwardly through the screen to the interior thereof, from which it is discharged, while the coarse material remains in the vat and from which it is removed. InV screens of this type, it is the common practice to remove the coarser materials from the bottom ofthe vat in which the screen operates through a valve which is left open to a certain degree or extent during the entire run of the vat. As will be appreciated, considerable fine stuf will pass out along with the water and the coarser'4 material through the open valve, thus allowing a lot of the stock and water to be discharged through the outlet pipe with a consequent loss of fine stuff.

Where the valve is not `left open it is necessary for the operator to open the same periodically for a short interval'of time, and under this operation it is found that the dirt and coarse material is liable to ll the vat suiiciently to stop up the screen openings or slots so that the fine stuf cannot pass therethrough and on its way tothe paper machine. Moreover the attendant is liable to forget to open the valve with the consequence that the discharge. may become plugged.

40 The present invention has for its main object the provision of means for automatically taking care of the removal of the coarser material, and for its further object means whereby the coarser material will be charge or the wellL'or pocket to which the valve is attached. 'd

The invention is illustrated in the annexed automatically fedr toward the valve dis- 1my 2nd, 1917, and to Bird, No. 1,301,258,

dated May 20, 1919;

Fig. 2 an end elevation thereof;

Fig. 3 an enlarged vertical sectional view illustrating the valve employed to control the discharge of the coarse stuff and dirt;

',Fig. 4 a vertical sectional view showing the detail of the valve and its seat, the secchamber in which the screen is` partially submerged, said vat being conne ted to the end frames 2 and 3 of the structu e by flexible connections as 4 and 5, which allow the vat proper to be moved or vibrated sidewise with reference to the end frames 2 and 3. Mounted within the vat is a rotatable screen 6, one end, as 7, of which is closed while the opposite end is open, and discharges through an annular member or collar 8 into an olftake or box 9. Rotary motion is imparted o the screen through a band pulley 10 hrough pinion 11, gear 12, pinion v13, and the relatively large gear 14. Said latter gear is splined to a shaft 15 which is mounted in a suitable bearing formed in the fixed frame 3, the inner end of the shaft being rigidly aixed to the closed end 7 of the screen.

The vibratory movement is imparted to the vat through any suitable mechanism which in the resent instance is shown as a shaft 16 carrying a cam 17, which latter imor rigid postor standard 21. The arm 19 is pivotally connected to the vat frame as at 22,

and said frame at its opposite side is sup- .ported upon yielding or spring members 2113,1100

one of which is shown 1n Fig.l 2. It w1 thus be seen that while the' screen partakesof'airotary motion, the vat is vibrated and this causesv the stuff within thev vatt? `surge against the screen andpermits theV nestulf to ass .inwardly througl1`the perforations int escreen.

Thebottom of the yiratfis rovided with a .vell or funnel-shaped 'mem r 24, 4adapted to receive the coarse material which settles in the lower portion of the vat. To facili- :tatevthe entrance of such material into the well or opening, I preferably .provide the outer surface of the screen with a series of s irally arranged or inclined blades or ights. Saidblades or flights, which are preferably provided with flexible wiping edges, are spaced at an angle tol each other and to the axis of the screen. The flighY are arranged in pairs spaced about the ou "r surface of the screen, the members of the various pairs' being preferably arranged at varying distances from each other, i. e., the members of one pair are arranged adjacent the ends of the screen as at 25, while the next succeeding pair are closer together as at ,26, and so on throughout the series until the -nal pair abut each other, as'at 27. Said last pair, as will be noted, stand in line with the discharge opening 24. These flights therefore gradually and constantly move the coarse stuff along the lower portion of the vat from the ends toward the discharge opening, and the final pair of flights 27 bring it directly over the funnel-shaped opening or discharge member 24.

Secured to the lower end of the funnel shaped discharge member 24,is an extension or mouthpiece 28 which has attached to it avalve casing 29 having a valve opening 30 adapted to co-operate with a valve 31' which is formed as an extension of an arm 32, said' arm extendinglaterally and to one side of the valve casing, as best shown in Figs. 1 and 3. Pivotally connected kto Vthe outer free end of said arm is a link 33 adjustable gas to length, said link in turn being connected to a lever 34 which is fulcrumed at 35, the opposite end of the lever in turn being connected to a rod 36, the upper end of which is attached/to a radius bar 37 pivotally secured, as at 38, to the end frame 3 of the machine. The pin 39 (seerFig. 5), which secures the rod 36 to the radius bar 37, forms thev support for a roller or bowl 40, which latter stands in the path of a cam 41 (see Flgs. 1 and f2), secured to the inner face of the gear 14 and extending outwardly into the path of the roller. The weight of the lever 34, the link 33, and the arm 32 Which 1s attached to the valve, is sufficient to hold the valve in its normally closed position, counteracting the weight of the short arm of the lever 34 to the right of the fjilcrum 35 and the weight of the rod 36 and the radius bar 37. For each revolution 'of the gear 14, the Vcam 41 will strike the roller 40 to depress the short arm of the lever 34 raising the opposite end and throw thfink 33, rocking the valve'from its closed position to thel open dotted line position shown in Fig. 3. The cam 41 is positioned on the gearl4 so that the valve will be o ened at approximately the time the ilig ts or scrapers I27- `come into alinement with the discharge where the workman is depended pon to open the valve from time to time. Again, no waste of fine stuff', other than a very small amount, takes placp. Again, the construction has the advantage of a-Hording a wide open valve with minor waste as contradistnguished from a small opening and a continued waste where the valve is -mechanically set to produce al 'constant discharge.

It is of course conceivable in the broader aspect of the linvention that the flights may be omitted and the'valve operated mechanically, but the presence of the flights, which act to gather the coarse material and bring it to the poi-nt of discharge, materially enhance the successful operation of the screen. Wash pipes for the interior and exterior of 4the screen are disclosed, but, as they form no part of the invention, specific reference thereto is omitted.

No claim is made herein speciicallytd the l flight or scraper arrangement,v other than in combination with'` the automatically operat' ing valve, as such flight' arrangement, as such, is not of my invention.

What I clalm is: j

1. In a screen for paper stock, the combinai means for rotating the screen, and mechanij cally actuated meansfor periodically opening the valve.

2. In a screen for paper stock, the combination of a vat having adischarge opening in the lower, portion thereof for coarse materia] and dirt, a screen mounted in the vat,

a valve controlling the discharge opening, means for rotating the, screen, and means working in timed relation with the screen for periodically opening the valve.

3. In a screen for paper stock, the combination afa vat having a discharge opening in the lower portion thereof for coarse materialand dirt, a screen mounted in the vat, means for rotating the screen, a valve con trolling thedischarge opening, andmeans associated with the screen-operating means for periodically opening the discharge valve.

4. In a screen for paper stock, the combination of a vat having adiischarge opening in the lower portion thereof for coarse material and dirt, a.I screen mounted in the vat, means for. notating the screen, means for oscillating the vat to produce a surging action therein with reference to the screen, a valve for controlling thedischarge opening, and mechanical means for perlodically opening the discharge valve.

5. In a screen for paper stock, the combination of a vat having a discharge opening in the lower portion thereof for coarse material and dirt; a screen mounted in the vat; means for rotating the screen; a series of vanes arranged obliquely with reference to the axis of the screen about ther outer surface thereof, said vanes servin by reason of their inclination to move t elcoarse material and dirt along the lower portion of the vat toward the discharge opening; a valve controlling said opening; and mechanically actuated means for periodically operating the valve. l

6.- In a screen for paper stock, the combination of a vat having discharge opening in the lower portion thereof for coarse material and dirt, a cylindrical screen mounted in the vat, means for rotating the screen, a series of {iights spaced at an angle to each other and ,to-the axis of the screen, said flights being secured to and spaced about the outer face of the screen in pairs, the members of the various pairs, in the series, beginnin at a. given point upon the screen, gradua ly approaching each other, a valve for controllmg thedischar e opening, and means for operating said va ve'm timed relation to the rotation of the screen, the parts being so arranged that the valve is opened when the pair of flights which are closest together come to jutaposition with the discharge opening.

7. In a. screen fo paper stock, the combination of a vat having a discharge open ing in the lower portion thereof for coarse material and dirt, a screen mounted in the vat, means for rotating the screen, a pivoted valve controlling the discharge opening, a cam associated with the screen operating means, and means extending from the valve and standing in line with the path of movement of the cam, said cam co-operating with said means tol open the valve.

In testimony whereof I have signed my 50 iication.

name to this y AMES HAMMOND. 

